Jadeite

A pyroxene with chemical formula of NaAlSi2O6. Jadeite occurs in high-pressure, low temperature metamorphic rocks and is the primary mineral in jade.
See pyroxene group for additional details.

Jefferisite

An obsolete name for altered material, probably vermiculite.

Jennite
K-bentonite

See bentonite.

K0 condition
Kalifersite

A member of the palygorskite-sepiolite group with a composition of (K,Na)5Fe3+7 (Si20O50) (OH)6 . 12(H2O). The kalifersite shows a regular alternation of structural components of sepiolite and palygorskite Ferraris et al. (1998).
See palygorskite-sepiolite group

Kaliglimmer

An obsolete term for muscovite.

kandite

discredited term, use kaolin-serpentine group (Bailey, 1980)

Kandite

Discredited term, use kaolin-serpentine group (Bailey, 1980).

Kandite

A name previously proposed for the kaolin/serpentine group. The name has not been approved for use by any mineralogical nomenclature committee and its use should be discontinued.